Diagnosis. A large species (TL up to at least 786 mm) of the genus Oligodon characterized by the combination of (1) 9 or 10 maxillary teeth, the last three or four strongly enlarged, (2) hemipenes not forked but divided into two lobes, thick and bulbous, reaching in situ the 16th SC, smooth, each lobe with a papilla, (3) 17–17–15 (or 17–15–15 DSR in one specimen); (4) cloacal plate entire, (5) complete complement of head scales, including 1 loreal on each side, (6) 8 supralabials (7 in one specimen), fourth and fifth (third and fourth in one specimen) entering orbit, (7) 184–193 ventrals in five males (females unknown), (8) tail relatively short in males (ratio TaL/TL: 0.135–0.146), (9) dorsal pattern made of a dark background colour with 27–37 darker, pale centered, butterfly-shaped blotches on the body and 5–8 on the tail, and (10) venter cream, heavily marked with dark pigmentation.